With a self optimizing fuzzy control system for CO 2 arc welding with filament wire,the arc voltage can be optimized for
certain given arc current to realize the maximum short circuiting transfer frequency.Consequently,the stability of droplets transfer can be improved to reduce the spatter and improve the formation of weld bead.However,the experimental results revealed that under the half short circuiting droplet transfer the arc voltage is generally maintained at about 20V with such control system despite arc current,which results in the formation of the narrow weld bead with a shallow penetration and large reinforcement.This fact suggests that there is a certain limitation with the self
optimizing fuzzy control of arc voltage only for the maximum short circuiting transfer frequency.Therefore a new control system with the
intelligent control through a PLC (programmable logical controller) was developed to realize the self optimizing control of arc voltage in half short circuiting welding.The system was primarily based on the control of arc voltage to search for both the higher transfer frequency and the longer ratio of burning arc time and short circuit time with variable steps.With such an optimization method,the optimized arc voltage was matched well with a given arc current to achieve a stable half short circuiting droplet transfer.